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R. LEHMANN. APPARATUS POR SUPERHEATING STEAM.

Patented Feb. 21,1882.,

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, INVENTOR ATTORNEY' I 000g) 0000 0000 0000 '//l//l/l/I//l//l//I/z//l/l//l//l//a WITNESSES x UNITED STATES PATENT OFFICE..

RICHARD LEHMANN, OF DRESDEN, SAXONY, GERMANY.

APPARATUS FOR SUPERHEATING STEAM.

SPECIFICATION forming part of Letters Patent No. 253,931, dated February 21, 1882.

Application filed November 14, 1881. (No model.) Patented in Germany September 4, 1880, in Austria October 6, 1880, and in Hun gary October 6, 1880.

useful Improvements in Apparatus for Superheating Steam, of which the following is a specification. l

This invention relates to improvements in the construction of apparatus for superheating steam, and to the application of such apparatus in the arts, the apparatus hein g mainl y intended to simplify all those portions ot' the superheating apparatus which are arranged within 'the furnace, so as to avoid as much as possible the necessity for repairs; secondly, to facilitate the repairs of any defective portion in a quick manner, so as not tointerrupt, or only for a short time, the working of the apparatus; thirdly, to enlarge the surface which takes up the heat as much as possible, so that the greatest amount of heat is developed with a comparatively small quantity of steam.

The invention consists in a system of superheating steam-pipes composed of an inner and an outer tube and a closed end tube, seid concentric pipes being united at the ends opposite the closed end pipes by a double set 0f U- shaped connections, as hereinafter described. In the accompanying drawings, Figure 1 represents a detail vertical longitudinal section of one of the heating-tubes of my improved superheating apparatus. Fig. 2 is a plan view, partly in section, of a series or system of the same. Figs. 3, 4, and 5 are details of the same. Figs. 6,7, and 8 are respectively a vertical longitudinal section, a side view, and an end view of a modified form of superheating-tube. Figs. 9 and 10 also show modiiied constructions of the same; Figs. 11 and 12, a dierent arrangement of the same; and Figs. 13, 14, 15, and 16 are vertical longitudinal and transverse sections, showing the application of my improved steam-superheating apparatus to, baking-ovens and drying-furnaces.

Similar letters of-reference indicate correspending parts. v

vided at one end with a detachable end tube,

C, of about the same or larger diameter than the tube B. The end tube, C, is closed at its outer end, and the inner tube, A, is extended into thc same to near the' closed end thereof. Theend tube, C, extends into the furnace ortirebox, and constitutes the superheating-surface, while the tube constitutes the radiating-surface. 'lhc opposite end of the exterior tube, B, is united to the end ofthe exterior tube,B, of a similar adjoining tube by means of a U- shaped coupling, D, the corresponding end of the pipe A projecting through the couplingD of the pipes B, and being also united to the interior pipe, A, by means of a U-shaped coupling, E. By continual connection of the projecting ends of the interior tubes, A, by means of the U-shaped coupling E, and of the exterior tubes by the couplings D, a system or battery of connected tubes is obtained. The steam enters tirst into one of the interior tubes,

. A, passes through the same, then through the closed end pipe, C, into the annular space inclose'd between the interior and exterior tubes, and finally through the connecting-coupling D into the exterior pipe, B, of the next adjoining superheatng-tube, and through the space between the exterior and interior pipes to the end pipe, and then through the interior pipe to the next superheating-tube, and so. on through -the entire system of tubes.

The advantageof this construction consists especially in the fact that only the closed end tubes, which are of simple construction and preferably of cast-iron, are exposed to the action of the gases of combustion, and that consequently in case of injury to any one of them only the defective end tube has to be ex changed. To accomplish this the U-shaped coupling E at the opposite side of the tube has to be unscrewed, whereby the entire tube becomes loose and can be withdrawn for screwing on a new end tube in place of the defective one.

To facilitate the 4detaehing of the connecting-coupling without detriment to the tube system--in other words, without interrupting the regular operation of the same-the tubes are made of such a length that the connections of the couplings are arranged outside of the furnace-Wall, and that they can, after removing their protecting-casing or other covering, be unscrewed from the outside.

The 'application of the superheating-tubes to a baking-oven is illustrated in Figs. 13 and 14, and in Figs. 15 and 1G the same system is applied to a drying or roasting oven. Whenever a direct action ot the steam-heat upon the material to be Worked up is desired-as, for instance, in retorts for distilling purposes and the like-the Walls of the vessels take the place of the exterior tubes, B, while interior channels take the pla-ee ot' the connecting-couplings, as shown in Figs. 9 to l2. The construction shown in these figures is simply a modification of the simplest form ot' superheating-tube shown in Figs. 1 to 5. Whenever the heating-furnace has to be placed either directly under the steam-superheating appa ratus or at some distance therefrom-as, for instance, in biscuit-ovens, air heating and dry ing apparatus, and the like-'the construction shown in Figs. 6 and 7 can be employed. In this case the exterior tube, B, takes the place ofthe cast-iron end tubes, C. (Shown in Figs. l to 5.) They are made with end anges and closed at one end. At this end are supported the interior tubes, A, of less diameter, which pass through the U-shaped couplings D at the opposite end of the exterior tubes.

The U-shaped couplings may be either of 3o semieircular shape, as in Fig. 8, or of the shape shown in Fig. 6, or of. any other shape adapted te the relative disposition ot' the superheatingtubes.

The superheating apparatus described can be applied with advantage to the arts for the purpose ot' admitting the higher utilization of the steam than heretofore.

Havingthus described my invention, I claim as neuT and desire to secure by Letters Patent- The combination of the interior and exterior tubes, A and B, closed end portions, C, attached to tubes B and extending into the fur nace, couplings D, connecting the tubes B, and couplings E, connecting the tubes A, the latter being arranged outside ot' the furnace, substantially' as speeied.

In testimony that l claim the foregoing as my invention I have signed my name, in presence of two witnesses, this 27th dav of September, 1881. e

RICHARD LEHMANN.

Witnesses:

PAUL DRUcKMULLnn, ROBERT Kom,

Both of flhcs'llcn. 

